Immune checkpoint inhibitors (ICIs) targeting cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed death 1 (PD-1), and PD ligand 1 (PD-L1) have revolutionized many cancers but have largely failed in PDAC, which exhibits primary resistance to monotherapy 10,11. Here, CTLA4 is linked to cancer.